2.0 Analysis 2.1 Introduction The analysis discusses the decisions made by the captain and the actions of the crew during the final seconds of the approach. The duty period, the emergency response, and the airframe ice will also be discussed. 2.2 The Approach 2.2.1 General The first officer, who had flown the en route portion of the flight, continued to fly the approach. The crew briefed for a 20-degree flap landing with a threshold speed of 114 KIAS prior to commencing the approach. The briefings and checklist items covered were in accordance with procedures given in the BA 31 Pilot's Handbook. Altitudes and airspeeds were monitored by the captain, the pilot-not-flying (PNF), throughout the approach. After the gear was selected down and flaps selected to 20 degrees, the airspeed decreased to 114 KIAS. This was corrected and the speed increased to 144 KIAS achieving a ground speed of 150 knots. The approach speed shown in the SOPs for a non-precision approach is 130 KIAS, so the speed of 144 KIAS was not a concern to the PNF as he was adding the additional 10 knots recommended for landing in icing conditions. The Alberta Citylink SOPs state that in icing conditions, the additional 10 knots is added to the landing speed, not to the approach speed. Although in itself the additional 10 knots added to the approach speed may be insignificant, when combined with other factors, the additional speed became a factor. The time available for the final descent from MDA was affected by the increased closure rate that resulted from the high ground speed. 2.2.2 Captain's Decision to Land Crew coordination, checklists, and approach monitoring were normal prior to reaching the minimum descent altitude of 2 640 feet as evidenced by the PNF calling low airspeed, altitude, and a reminder at 2 and 2 miles for the pilot flying (PF) to remain on the instruments as the airport environment was not visual. When the PNF obtained visual contact, he indicated that he had control of the aircraft which may have surprised the first officer. After seven seconds of information exchange, it was decided that the captain would land the aircraft. The ground speed put the aircraft closer to the runway, and a number of actions took place that de-stabilized the approach; power was reduced to flight idle, flaps were selected to 35 degrees despite the fact that 20 degrees of flap was briefed, and two turns were made to line up with the runway. This set up a high rate of descent as the aircraft descended from 457 feet agl in 16 seconds. An aircraft on a stabilized approach at an airspeed between 121 and 140 knots will take about 16 seconds to descend from 200 agl. In the conditions that existed; visibility reduced in snow showers, darkness, and a concentration on the landing area, the captain did not arrest the rate of descent prior to contact with the runway. The forces generated by the sudden deceleration combined with a left-to-right movement collapsed the undercarriage, and the aircraft skidded down the runway on the belly pod and the damaged right main gear. The power was reduced and the flap selected to 35 degrees because, at the high ground speed, the runway was approaching fast, and the captain believed that this action was required to make the descent to the touchdown point. The selection of 35 degrees of flap made the lift dump capability available to increase the drag after touchdown and decrease the landing distance. The airspeed decay and variations in descent rate on short final are considered characteristic of an unstabilized approach. Selecting the power to flight idle prior to touchdown in the Jetstream 31 is not recommended due, in part, to the increased drag created by the propellers. Normally, on approach, between 18 to 20 per cent power is used and is gradually reduced to flight idle during landing flare. Just prior to the impact, power was increased, but there was insufficient time to overcome the inertia of the descending aircraft. 2.2.3 Actions of the First Officer After the captain took control of the aircraft for the landing, the first officer performed the duties of the PNF and, in accordance with the captain's requests, he lowered the flap, turned the landing lights on, and reported to the FSS that the flight was landing. Although the time was short, the first officer did not make any calls to indicate that the aircraft was descending at a high rate of descent. The company manuals do not indicate action required should an approach become unstabilized. 2.2.4 Duty Period Following three days off, both pilots reported for duty at 0600 the morning of the accident. Their flying was to consist of three return flights to Lloydminster arriving back in Calgary about 1940. This is a planned duty period of 12 hours and 40 minutes. Between the morning and the afternoon flight, there is a four-hour layover in Calgary. The same crew normally does this flight three days in a row before days off are taken. On the day of the accident the first flight in the morning was delayed due to poor weather at Lloydminster. The weather did improve, and the two return flights to Lloydminster were uneventful. Although the duty periods are scheduled in accordance with Canadian Aviation Regulations (CARs), the working days are of long duration, and, on a day when flights are delayed and when weather impacts on the decision making process, fatigue can be a factor. 2.3 Emergency Response The emergency response services were requested by the FSS specialist at the time of the accident, and they responded from the city. It took about 17 minutes for the vehicles to arrive. In this case, there was no fire or injuries. Those responsible for the operation of airports, in consultation with Transport Canada (TC) and the airlines, have done a risk assessment and determined that emergency response from the local community meets the requirements. 2.4 Airframe Ice During the descent, the flight encountered icing conditions that were described by the crew as moderate, however, the accumulation was under inch, the minimum amount stated in the Flight Manual to operate the de-icing boots. In the company SOPs, it is stated that the boots must be cycled prior to selecting flaps. These two instructions appear to be in conflict. The aircraft had under inch of ice on the leading edges of the wings, horizontal stabilizer, and vertical stabilizer. The aerodynamic effects associated with ice accretion and their influence on this aircraft's recovery from a high rate of descent were not determined. 3.0 Conclusions 3.1 Findings The flight crew were licensed and qualified for the flight in accordance with existing regulations. The aircraft was certified, equipped, and maintained in accordance with existing regulations and approved procedures. There was no evidence found of any airframe failure or system malfunction prior to or during the flight. Weather conditions were adverse, but within limits for a night instrument landing. When the captain saw the airport environment, he assumed control of the aircraft for the landing. There was a delay of seven seconds before the final descent was commenced. The final segment of the approach to landing was unstable due to the reduction of power to flight idle, the manoeuvring turns, and the time available for the final descent. The high rate of descent that developed was not arrested prior to touchdown. The aircraft landed hard, while drifting to the right, collapsing the left main gear and damaging the right main gear. Examination by the TSB Engineering Branch of all broken landing gear components indicated that the failures were overload in nature. The Flight Manual and Alberta Citylink SOPs differ in the recommended procedure for operating the de-ice system prior to selection of flaps. 3.2 Causes An unstabilized approach resulted in a heavy landing because the captain changed the configuration of the aircraft, and the high rate of descent that resulted was not arrested before contact was made with the runway surface. Contributing to the high rate of descent were the reduction of engine power to flight idle, airframe ice, and the time available for the final descent. Contributing to the damage on landing was the left to right movement of the aircraft.